LOS GATOS -- A collective wave of heartache and nostalgia washed over the town after the Happy Hound, a venerable hot-dog franchise that slowly but surely morphed into a landmark, was heavily damaged by a fire early Monday.

Owner Dan Dresslar is vowing to rebuild and reopen within a month, even as he admits that might be a bit optimistic.

The one-alarm fire was reported at 4:48 a.m. and spread through the roof and a storage area, according to the Santa Clara County Fire Department. Dennis Johnsen, chief fire investigator, estimated damage at $100,000 but said much of the interior of the restaurant was unscathed, except for the lingering smell of smoke.

Santa Clara County Fire arson investigators look through the rubble at the Happy Hound restaurant in Los Gatos, Calif. on March 4, 2013. (Gary Reyes)

Dresslar, whose parents opened the Happy Hound 42 years ago, lives near the restaurant and was awakened by firefighters.

"It's devastating," Dresslar said. "I couldn't believe it when I walked out of the house. It's my whole livelihood."

The fire was reported by a passer-by, who saw flames coming out of the side of the restaurant, Johnsen said. Firefighters spent about 30 minutes extinguishing the blaze.

The fire seems to have started in a storage area and likely stemmed from a faulty or overloaded electrical strip, Johnsen said.

Dresslar was keeping his spirits up as friends loaded bags of buns, onions, hot dogs and burgers into vehicles. The food was donated to Second Harvest Food Bank.

"It's a good thing it happened when it did because Monday is when our food is delivered," Dresslar said. "I've had to cancel all the deliveries."

The eatery was actually a second incarnation after Dorothy Dresslar opened the original Happy Hound (then named the Hound Dog) in Danville in 1968, serving only hot dogs, bags of potato chips and canned soda. Three years later, in 1971, the family brought it to Los Gatos Boulevard just a stone's throw from Blossom Hill Road.

Happy Hound employee David Michaels at the restaurant in 2011. (Photo by George Sakkestad)

Dan Dresslar bought and took over the restaurant in 1987, and over time the menu expanded from hot dogs to include hamburgers, to the point where there was a playful debate over whether it was a hot-dog stand -- even as its modest footprint included indoor seating -- or a burger joint.

When the restaurant threw a 40th anniversary bash two years ago, fans commemorated what had grown from something residents once thought would open the floodgates for traffic headaches and the proliferation of fast-food dives to a beloved staple of the community.

In one instance, a woman bought four dogs and had them flown to her mother in Hawaii.

Dresslar said several customers stopped by the restaurant Monday morning and offered support and encouraged him to reopen for business quickly.